Substituted benzimidazoles

ABSTRACT

Benzimidazoles of the formula   WHEREIN R1 is alkyl, R2 is alkyl, cyclo-alkyl, benzyl or phenyl, SR2 being in 2- or 3-position, R3 is hydrogen, alkyl, aliphatic saturated alkanoyl, chlorine, bromine, cyano, methoxy, ethoxy, phenoxy, phenylthio or benzoyl, and R4 is hydrogen, chlorine or methyl are valuable fungicides and anthelminthics.

United States Patent Dransch, deceased et al.

SUBSTITUTED BENZIMIDAZOLES Assignee: Hoechst Aktiengesellschaft,

Frankfurt am Main, Germany Filed: Jan. 24, 1974 Appl. N0.: 436,356

Foreign Application Priority Data Jan 27 1973 Germany 2303999 US. Cl.. 260/309.2; 260/453 AP; 260/453 PH;

260/464; 260/544 C; 260/563 P; 424/273 Int. C1. C07D 235/32 Field of Search H 260/3092 Oct. 28, 1975 [56] References Cited UNITED STATES PATENTS 3.660.421 5/1972 Osieka et al. 260/3092 3,705,173 12/1972 Adams et al 260/3092 3.738995 6/1973 Adams et al 260/3092 Primary Examine'r-Sherman D. Winters Attorney, Agent, or FirmCurtis, Morris & Safford [57] ABSTRACT Benzimidazoles of the formula O: C-NH-CH wherein R is alkyl. R, is alkyl cycloalkyl. benzyl or phenyl, SR being in 2- or 3-position, R is hydrogen. alkyl, aliphatic saturated alkanoyl, chlorine bromine, Cyano, methoxy, ethoxy phenoxy phenylthio or benzoyl, and R is hydrogen, chlorine or methyl are valuable fungicides and anthelminthics.

8 Claims, No Drawings a-i: I

HCOOR R N 1 I SUBSTITUTED BENZIMIDAZOLES Subject of the present invention are benzimidazoles having the formula 3 HCOOR I u 1 V R ,G-NH-Cl'l SR wherein 1 R represents alkyl having from 1 to 4 carbon atoms, R represents alkyl having from 1 to carbon atoms, cycloalkyl having from 5 to 8 carbon atoms, benzyl or phenyl, each being in 2- or 3-position R represents hydrogen, alkyl having from 1 to 4 carbon atoms or alkanoyl having from 1 to 4 carbon atoms, chlorine, bromine, cyano, methoxy, ethoxy, phenyloxy, phenylthio or benzoyl, and R represents hydrogen, chlorine or methyl, as well as mixtures of the isomers obtained by interchanging R and R Another subject of the invention is a process for preparing the compound of the formulal which comprises reacting a. a benzimidazole having the formula 3 Ill- COOK 11 with an isocyanate having the formula --m:o I III or with a carbamic acid halide having the formula R S HZNHCOCI (Br) Iv b. a derivative of a chloro (or bromo) carbonylbenzimidazole having the formula with an amine having the formula The most advantageous method of preparing the compound according to the invention according to process (a) consists in suspending a benzimidazole derivative of' the formula II in an inert solvent such as dimethyl formamide, methyl ethyl ketone, methylene chloride, chloroform, chlorobenzene, tetrahydrofurane, or acetonitrile and mixing it, while stirring, with an approximately stoiehiometric quantity of an isocyanate having the general formula lll, preferably operating at temperatures ranging from +5 to +55C. Generally, the reaction periods last from about 1 to abt. 8 hours.

If the reaction starts with carbamic acid halide having the formula IV, same is first prepared by adding at about 0 to C an amine having the formula VI to a solution of phosgene in an inert organic solvent such as benzene or tetrahydrofurane, by subsequently filtering off the hydrochloride of the amine and by eliminating excess phosgene by distillation in vacuo. Next is added an approximately stoichiometric quantity of the benzimidazole derivative having the formula ll, followed by the addition of an acid binding agent, for example a tertiary amine or potassium carbonate. This reaction step is generally carried out at a temperature from 0 to C, the subsequent work-up being performed as usual.

In process (b), in the first phase, for example, a derivative of Z-benzimidazole having the formula ll is treated at about from 20 to +20C with a solution of phosgene in an inert organic solvent, subsequently an equivalent quantity of a tertiary amine such as dimethylaniline, triethylamine or pyridine is added finally the hydrochloride is separated. After having eliminated the excess phosgene by distillation, the product is re acted with twice the stoichiometric quantity of an amine having the formula VI within a temperature range from about 0 to C and worked up as usual.

As per formula ll or V the following compositions may, for example, be used as starting products for the preparation of the compounds according to the invention.

2-methoxy-, 2-ethoxy-, 2-n-propoxy-, 2-isopropoxy-, 2-butoxy-, 2-isobutoxy-carbonylamino-benzimidazole, 5(6)-methyl-, 5-(6)-ethyl-, 5(6)-butyl-, 5(6)-sec.butyl- 5(6)-tert.butyl-, 5(6)-yano-, 5(6)-chloro, 5(6)- bromo-, 5(6)-methoxy-, 5(6)-phenylmercapto-, 5(6)- phenyloxy-, 5(6)-acetyl, S-phenylmercapto-7-chloro-. 5,6-dichloro-, 5,6-di-methyl-, 5-chloro-6-butyl-, 4,6- dichloro-2-methoxy-(ethoxy-, propoxy-, butoxy-)- carbonylaminobenzimidazole.

These initial compounds are reacted with compounds having the formula lll, IV or Vl, wherein R represents methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert.butyl, pentyl, 3-methylbutyl, Z-methylbutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, benzyl, or phenyl.

In part the initial compounds having the formula ll are known, partially they are accessible through known preparation processes (cf. US. Pat. No. 2,933,502).

Since both nitrogen atoms are equally available for reactions at the imidazole ring, it is often difficult to determine positively whether, if the compound contains two substituents R and R The substituent R is in 5- position or, rather, the substituent R The same is true not uniform. However, this has no adverse effecton either the fungicidal or the anthelminthic effect.

The compounds of formula III are obtained by addition of a mercaptan having the formula R SH to a 2- isocyanatomethylbicyclo [2,2,1 l-heptene. It is, however, more advantageous to prepare first a compound having the formula VI:

g4; R SH SR H N-CH, H N--CH, I CH" SH R SH They are obtained by reacting 2-aminorhethylheptene or 2cyanobicyclo' [2,2,11--heptene with a mercaptan having the formula R SH, the cyano group in case a nitrile is used 4 being subsequently reduced by means of a catalyst or of LiAlH The amines of the formula Vl thus obtained may be transformed in the usual manner by phosgenation into the corresponding isocyanates or carbamic acid chlorides.

The compounds according to the invention have outstanding fungicidal properties and an especially broad spectrum of effectiveness. Having a very low toxicity for warm-blooded animals and protective as well as curative systemic properties, they can be used particularly for protecting crop plants in agriculture.

Due to their systemic properties, they can further be used for the treatment of seed or soil so as to subdue fungal diseases developing on the seedling. On the other hand, the compounds according to the invention are also efficient on dead organic material and may therefore be used to protect, for example, pigments, oils, wood, leather, protein, paper and textiles from fungus attack.

Without claiming to are complete, the following fungi be cited as being effectively combated by the compounds of the invention:

Erysiphe cichoracearum Piricularia oryzae Pellicularia sasakii Fusarium nivale Rhizoctonia solani Verticillum alboatrum Fusarium solani The fungicidal agents of the invention contain from 5 to 90 of a benzimidazole having the formula (I) as active compound in the usual formulations in combination with solid or liquid additives such as inert carriers, adhesives, wetting and dispersing agents and grinding auxiliaries. They may be used as wettable powders, emulsions, suspensions, dusting powders or granules. They can also be mixed with other fungicides with which they form mixtures of good compatibility.

As carrier material, mineral substances may be used, such as aluminium silicates, argillaceous earths, kaolin, chalks, siliceous chalks, talcum, kieselguhr or hydrated silicic acids, or preparations of these mineral substanceswith special additives, for example chalk with sodium stearate. As carrier material for liquid preparations, all usual and suitable organic solvents may be employed, for example toluene, xylene, diacetone alcohol, cyclohexamone, isophorene, gasolines, paraffin oils, dioxane, dimethyl formamide; dimethyl sulfoxide, ethyl acetate, tetrahydrofuran, chlorobenzene and the like. i

As adhesives, there may be used glue-like cellulose products or polyvinyl alcohols.

As wetting agents, all suitable emulsifiers may be used, such as oxethylated alkylphenols, salts of arylor alkylaryl-sulfonic acids, salts of oleyl methyl taurine, salts of oxethylated phenyl sulfonic acids, or soaps.

Suitable dispersing agents are cellulose pitch (salts of lignin sulfonic acid), salts of naphthalenesulfonic acid or salts of oleyl methyl taurine,

As grinding auxiliaries, suitable inorganic or organic salts, such as sodium sulfate, ammonium sulfate, sodium carbonate, sodium bicarbonate, sodium thiosulfate, sodium stearate or sodium acetate may be used.

The products of the invention are also suitable for combating parasitic diseases of warm-blooded animals, especially helminths.

They are characterized by a particularly strong anthelminthic effect, combined with a good compatibility, against gastrointestinal strongyles to which ruminants are especially prone. These parasites can cause enormous economical damage to animal breeding. Therefore, the products of the process represent valuable medicaments. In practice, the ant helminthics are administered orally or subcutaneously, the preferred application form depending on the special circumstances. For oral administration suspensions having concentration from 1-50 powders dispersable in water (concentration from l preferably from 40-70 pastes as well as granules of various concentrations; for parenteral treatment sterile solutions of variable concentration are used. Various additives are required so as to guarantee good distribution, stabilization and preservation ofthe active agent aswell as a better resorption. Talcum, lactose, magnesium stearate, aerosil, starch or polyethylene-glycol are preferred.

The following examples illustrate the invention:

EXAMPLES OF PREPARATION:

EXAMPLE 1 2-aminomethyl-5-( 6 )-ethylmercaptobicyclo[2,2,l1heptane a. The mixture of 92.5 grams of Z-aminomethylbicyclo[2,2,l]Z-heptenev and 51.5 grams of ethylmercaptan is stirred in 150 ml of chlorobenzene at 45C for 19 hours while adding 05 gram of azodiisobutyricacid-nitrile; after. another addition .of 0.5 gram of azodiisobutyric-acid-nitrile stirring is continued for another 4 hours at 60C and a final 4 hours at C. Subsequently, the chlorobenzene is eliminated by distillation in a water, jet ,;vacuum, and 2-aminomethyl-5(6)- ethylmercapto-bicyclo[2,2,l]heptane is obtained by fractional distillation.

Yield: 127 g, (92.5 of theory)bp 83-85C.

b. To the suspension of 24.6 grams of LiAll-l, in 500 ml of ether are added, while stirring, within 45 minutes, after nitrogen. replacing the air in the flask 91 g of 2- cyano-5 (.6 ethylmercaptobicyclo[ 2,2,l 1 -heptane. Subsequently, the suspension is kept at reflux temperatures for 2 hours. Finally, 140 ml of water and 40 ml of 15 NaOH are added dropwise under ice cooling. Solid matter is filtered off the ethereal solution, the latter is dried over KOH, and first the ether and then the bicyclo[2,2,l]heptane are added; then the mixture is stirred for 4 hours at room temperature. The chloroform is eliminated by distillation in a water jet vacuum, the residual oil is triturated with a mixture of 120 ml of residual oil are distilled off 76 g (82 of theoretical 5 gasoline and 30 ml of ether for crystallization. yield) of 2-aminomethy1-5(6)-ethylmercapto- The yield i -l hy m r p bicyc1o[2,2,1]heptan p 95C are obtained. biCyC10[ 2',l ,1]hepty1-6'-methylcarbamoyl]-2- methoxycarbonyl-aminobenzimidazole having a de- EXAMPLE 2 composition point between 6466C is 160 g (76.4 2-isocyanatomethyl-5(6)-ethylmercaptoof theory).

bicyclo[2,2,l l-heptane C l-1 N O S (MW 402.53).

- o Anal sis:

a. 130 g of phosgene are introduced at O C into 800 59.68 ua- 13-92 7'97 (7. ml of chlorobenzene, 200 g of ammomethyl-(6)- Found. C 594 H 6 8 L7. N 13 7 S 7 7 ethylmercapto-bicyclo[2,2,l ]-5-heptane added drop- 15 I wise while stirring and continuing the introduction of phosgene, and the temperature is increased slowly to EXAMPLE 4 120C over a period of 8 hours. After the deposit has 1-[2'(3)-ethylmercapto' almost completely dissolved excess phosgene is blown bicyout at 60C through a nitrogen current, the chloroben- 30 clo[2,2,1- zene is eliminated by distillation in a water yet vacuum heptyl-6'-methylcarbamoyl]-2- and subsequently the 2-isocyanatomethyl-5(6)- methoxycarbonylamino-5(6)-phenylmercaptoethy1mercapto-bicyc1o[2,2,1]heptane is fractionated. I vbfinZiIIlidilZOlE Yield: 2.08 g (82 Of theory) plj 125C s To the suspension of g 2- CHHWNOS (MW 21 methoxycarbonylamino-S-pheny1mercapto- Analysis: benzimidazole in 200 ml of methylene chloride are C3101 -17 added 6 g of 2-isocyanatomethyl-5(6)-ethylmercapto- Folmdl 64 bicyclo [2,2,1]heptane, the mixture is stirred at room b. In a stainless steel autoclave 400 g of toluene, 59,6 temperature for 5 hours, the residue is filtered off and g of 2-isocyanatomethyl-bicyclo[2,2,1]S-heptene and the methylene chloride is eliminated by distillation in 26,2 g of ethylmercaptan are stirred, after addition of a water jet vacuum. The residue, which is first of oily 0.3 g of azodiisobutyric-acid-nitrile, first for 2 hours at nature, is triturated with gasoline for crystallization. 80-90C, subsequently for 6 hours at l-l60C, the 13 g of h ry) of hylm p mixture is cooled and fractionated. 35 N 3 3 lp y y y l- 35.2 g of 2-isocyanatomethyl-5(6)-ethylmercaptoh y y P y m p bicyclo [2,2,1]heptane are obtained, bp benzrmidazole decompos1t1on point from to 172C are obtained EXAMPLE 3 C H N O S (MW 510.7) 1 Anal sis: l [2 (3 i 40 Calcz C,61.16 H, 5.92 7:; N, 10.97 7c; S, 12.56

c1o[2',2',- y

Found: C, 61.0 70; H, 6.1 70; N, 11.2 7c; S, 12.4 70. heptyl 6 umethykarbamoyl]tz-methoxycaru The compounds specified in the following table were bonylammo'benzlmldazole 45 obtained according to Examples (3) and (4) by react- To a suspension of 99.5 g of 2-methoxycaring an isocyanate having the formula III with a benzbonylamino-benzimidazole in 1400 ml of chloroform imidazole derivative having the formula 11, wherein R 1 10 g of 2-isocyanatomethyl-5-(6)-ethylmercapto- R R and R have the meanings specified above.

TABLE Example formula decomp. pt. Analysis ("C) calc. found 5 m NH-COOCl-l 92 1 .82 N 13.1

o'=c' -Nn cu sc n,

6 L NI-I-COOCH 13.46 N 13,1

TABLE-Continued Example formula decomp. pt. Analysis (C) calc. found 10.03 N 9,6 33 NH-COOCH 65-68 64.50 C 64,81

EXAMPLES OF APPLICATION:

EXAMPLE I Winter wheat was sprayed to the drip-off point with aqueous suspensions of the compounds listed in table I. The concentrations applied were 120, 60 and 30 mg of active agent each per liter of spray liquor. Comparative agents were Benomyl (comparative agent I) and benzimidazole-2-carbamic-acidmethyl-ester (BCM comparative agent II).

The spray layer dried, the plants were infested with conidiae of powdery mildew of wheat (Erysiphe grarninis) and placed in a greenhouse, where the temperature was 22C and the relative humidity was from 80-90 After a days incubation period the plants were examined for contamination with powdery mildew of wheat and the infestation was judged by visual inspection. The degree of infestation is expressed in 7r of infested leaf surface as compared to untreated infested control plants. Table I shows the result of the test.

EXAMPLE ll Sugar beet plants were infested at the 6-leaf stagc with conidiae of Cercospom betimla causing beet leaf spot and placed dripping wet in a chamber having a temperature of C and a relative humidity of 100 7c. The plants remained in this chamber for one day and were then placed in a greenhouse having a temperature of from 25-26C and a relative humidity of from 85-90 After a 5 days incubation period the plants were treated with aqueous suspensions of the compounds and comparative agents shown in table II, applied in concentrations of 250, 125, and 60 mg of active-agent per liter of spray liquor.

The spray layer dried, the plants were transferred back to the green-house and examined by visual inspection for infestation with beet leaf spot after an incubation period of 3 weeks. The infestation is expressed in of contaminated leaf surface as compared to untreated infested control plants.

The results of the test are shown in table ll.

EXAMPLE lll Tomato plants of the variety Rheinlands Ruhm were infested at the 3-leaf-stage with conidiae of Cladosporium fulvum causing leaf mould of tomatoes and placed for 24 hours in a chamber having a temperature of 25C and a relative humidity of 100 Subsequently, the plants were placed in a greenhouse having a temperature of from 25 to 26C and a relative humidity of from 85-90 '76.

After a 5 days" infestation period the plants were sprayed dripping wet with aqueous suspensions of the compounds and comparative agents specified in table lll, in concentrations of 250. 125 and 60 mg of active agent per liter of spray liquor. Upon drying of the spray layer the plants were transferred back to the greenhouse.

After an incubation period of 3 weeks the plants were examined by visual inspection for their contamination with Cladosporium; the degree of infestation is expressed in table lll in 7( of contaminated leaf surface as compared to untreated infested control plants.

EXAMPLE lV Winter wheat was mixed in 4 repetitions for 10 minutes in a shaking machine with the compounds and comparative agents specified in table IV in concentrations of 400, 200 and 100 mg of active agent per 100 kg of seed. Subsequently. 10 grains each of the treated seed in 5 repetitions were sown in earth-filled pots and placed in a greenhouse. After emerging and attaining the 4-leaf-stage the plants were infested with conidiae of powdery mildew of wheat (Erysiplu' graminis) and placed in a greenhouse having a temperature of from 2()22C and a relative atmospheric humidity of from -90 7t.

After an incubation period of l() days the plants were examined by visual inspection for contamination with powdery mildew, the degree of contamination being expressed in 7r of contaminated leaf surface as compared to untreated infested control plants.

The results are shown in Table IV.

EXAMPLE V (Anthelminthics) The compounds having formula I were tested on sheep which were infested for the experiment with various types of gastrointestinal nematodes. At the end of the prepatency period (the lapse of time between infestation and pubescence of the parasites upon the beginning of egg production) the number of eggs per gram of excrement (EpG) was determined by an ameliorated version of the McMaster procedure (Wetzel, Tieraerztl.Umschau 6, pg. 2092l0,-v 1951), and subsequently the sheep passed a single oral or subcutaneous treatment. At several given moments after the treatment according to McMaster the number of eggs per gram of excrement was determined and their reduction (in percent) calculated as compared to the initial value.

Table V shows the action on gastro-intestinal strongyles of compounds according to the invention as related to the comparative agent Thiabendazol.

EXAMPLE Vl Moreover, the efficiency of the products of the invention as anthelminthics can be demonstrated by a 15 16 further test involving a larger animal (see table VI). Table VI! The proof of efficiency is provided by a dog infested for Compound this experiment with ancyclostoma, whose output of g gggi i 2f aWham)" effect ancylostoma eggs is checked repeatedly accordmg to p g f 80 7 the McMaster procedure. The reduction 1n percentage 5 3 5 Sig: 100 of the number of eggs lS calculated by comparing the 13 10 [1.0. 65 quantity of ancylostoma eggs found before the treat- Thlabefldfllol 500 .oi 82 ment and afterwards. "Novilla Mr N. and R. F. Flauta. Philli J. VeL'Mcd 6. 135-l44, 1967 Table I Table ll Compound 7: Leaf contamination with Leaf contamination with Cercoaccording powdery mildew of wheat spora on carrots at mg to example at mg of active agent/ active agent/liters of spray liters of spray liquor liquor lZO 6O 30 250 125 60 3 l2 0 O 3 l2 0 l0 l5 0 O 8 l4 0 8 l5 0 O 5 21 O 5 1O 0 O 3 28 O l0 l5 0 0 12 29 0 8 l5 0 O 8 3O 0 1O 18 O 0 10 cf. agent I O 8 l4 0 0 5 benomyl cf. agent ll 3 I8 l0 18 28 BCM untreated infected I00 I00 100 100 100 [00 plants Table III Table IV Compound 7: Leaf contamination with 7: powdery mildew contamination on according Cladosporium on tomatoes at mg winter wheat at mg active agent/ to example of active agent/liters of 100 kg of seed spray liquor 250 I25 400 200 lOO 3 O 5 l0 O O 8 l2 0 8 l5 0 O l0 l4 0 5 12 O 0 5 2i 0 8 l5 0 O 8 28 0 1O 18 O 0 1O 29 O 8 l5 O O 8 3O 0 12 2O 0 0 12 cf. agent I O 8 l5 0 0 10 benomyl cfv agent ll 5 i2 36 O 2 l5 BCM untreated infected I00 I00 I00 100 lOO 100 plants Table V Table VII Com d 55 poun (toxicity) according D.c.mi application effect Compound Tolerance (Dosis tolerata maxima) to example mg/kg according with single application of the white to example mouse 3 20 p.o. 100 VI 20 s. 19 20 f 3; 3 oral: 800 mg/kg 4 0 PM 1 60 subcutaneous: 400 mg/kg 5 90 (7 19 Oral: 16OO mg/kg Thiahendazol 50 poor 99 7: Subcutaneous: I600 mg/kg l2-(4-Thiazolyl) 20 5.0. 0 71 i 4 Oral: 800 mg/kg hcnzimiduzol] subcutaneous: 200 mg/kg "'l-lntnn. L, (L. 0. Hr Sicgmund. A. Dv Rankin and R. G Bramcl Texas Rcp. Biol.

We claim r l. A benzimidazole having the formula J HCOOI{ R N 1 I wherein R, represents alkyl having from 1 to 4 carbon atoms. R represents alkyl having from l to 5 carbon atoms. cycloalkyl having from 5 to 8 carbon atoms, benzyl or phenyl, SR being in 2- or 3- position R represents hydrogen. alkyl having from 1 to 4 carbon atoms or alkanoyl having from l to 4 carbon atoms, chlorine bromine. cyano. methoxy. ethoxy phenyloxy, phenylthio or benzoyL and R represents hydrogen. chlorine or methyl, or mixtures ofo the isomers obtained by interchanging R; and R 2. The compound of claim 1 which is 1-[2'( 3' ethylmercapto-bicyclol 2',2 ,l ]-heptyl-6'- methylcarbamoyl ]2 methoxycarbonylamino- V benzimidazole.

3. The compound of claim 1 which is l-[2(3)- ethylmercapto-bicyclol 2 ',2"l ]-heptyl-6'- methylcarbamoyl ]-2-methoxycarbonylamino-5( 6 phenylmercapto-benzimidazole.

4. The compound of claim 1 which is 1-[2-(3)- ethylmercapto-bicyclo[ 2',2',l ]-heptyl-6- methylcarbamoyl ]-Z-butoxycarbonylaminobenzimidazole.

5. The compound of claim 1 which is propylmercapto-bicyclo 2 ',2 ,1 ]-heptyl-6'- methylcarbamoyl ]-2-ethoxycarbonylaminobenzimidazole.

6. The compound of claim 1 which is butylmercapto-bicyclol 2,2,l ]-heptyl-6- methylcarbamoyl ]-2-methoxycarbonylamino-5( 6 phenoxymercapto-benzimidazole.

7. The compound of claim 1 which is l-l2'(3')- propylmercapto-bicyclo[ 2',2 .1 ]-heptyl-6'- methylcarbamoyl ]-2-mcthoxycarbonylamino-5( 6 phenylmercapto-bcnzimidazole.

8. The compound of claim I which is l-[Z'(3')- phenylmercapto-bicyclol 2'.2,l ]-hcptyl-6'- methylcarbamoyl ]-Z-methoxycarbonylamino-5( 6 phenylmercapto-bcnzim idazolc. 

1. A BENZIMIDAZOLE HAVING THE FORMULA
 2. The compound of claim 1 which is 1-(2''(3'')-ethylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -methoxycarbonylamino-benzimidazole.
 3. The compound of claim 1 which is 1-(2''(3'')-ethylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -methoxycarbonylamino-5(6)-phenylmercapto-benzimidazole.
 4. The compound of claim 1 which is 1-(2''-(3'')-ethylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -butoxycarbonylamino-benzimidazole.
 5. The compound of claim 1 which is 1-(2''(3'')-propylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -ethoxycarbonylamino-benzimidazole.
 6. The compound of claim 1 which is 1-(2''(3'')-butylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -methoxycarbonylamino-5(6)-phenoxymercapto-benzimidazole.
 7. The compound of claim 1 which is 1-(2''(3'')-propylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -methoxycarbonylamino-5(6)-phenylmercapto-benzimidazole.
 8. The compound of claim 1 which is 1-(2''(3'')-phenylmercapto-bicyclo(2'',2'',1'')-heptyl-6''-methylcarbamoyl)-2 -methoxycarbonylamino-5(6)-phenylmercapto-benzimidazole. 